Numerous systems have been developed over the years which utilize telephone lines, power lines and CATV lines for carrying signals of all types representing alarm conditions, data readings, survey data, and various types of control signals to initiate control functions. Such systems are attractive from an economical point of view in that they take advantage of existing transmission media and, therefore, like radio and television, make possible long-range communications and transmission of control and data signals without large expenditures for the transmission media itself. However, such systems have to date been used for the most part for the transmission of alarm, survey and control signals and have been generally unavailable to the individual subscriber for handling a broader range of data communications and services, and those systems which are in use require dedicated access to the data service, which is expensive and inefficient.
Television has greatly increased the communication of data to the home over that provided by radio in that it involves both a visual and aural commuication. However, commercial television, like radio, provides a unilateral service in that the viewer basically is capable of receiving only that which others wish to transmit at any given time. Prior services systems which utilized the telephone, power and CATV lines were also, for the most part, unilateral systems in that such systems were designed to transmit information only in a single direction, i.e, from the subscriber to power, security and other service companies. In those systems designed for remote meter reading and audience survey, control signals were transmitted to individual subscribers and in response thereto the data was transmitted automatically to the collecting agency; however, in these systems the subscriber had little or no control over the information being transmitted and certainly had no power or capability of envoking the receipt of data on request.
The world is presently at the doorstep of the next great advance in the extension of data services to the private sector of the community. Data processing systems have already become the indispensable tool of the business and scientific communities, providing word processing, data retrieval, systems analysis, reservations control and may other services on various levels of sophistication. However, such services can also be made available to the individual subscriber in his home by way of available telephone lines. The provision of multiple services to the telephone subscriber represents a fascinating prospect for the future, which encompasses a broad range of technologies for delivering such services, including satellite, coaxial cable and fiber optic systems.
However, in systems designed to handle both alarms and data communication, problems are encountered in handling both types of signals without undue complexity and without having to buffer the data and interleave it with the alarms. In addition, where multiple services are to be made available to the subscriber, some means must be provided to access different types of terminals at the customer premises on a selective basis in a way which is compatible with the reporting of alarms and other conditions as desired.
It is therefore a broad object of the present invention to provide a multiple service broadband system for existing telephone local loop service.
It is a further object of the present invention to provide a system of the type described which will be transparent to normal telephone service while providing a multiplicity of new services including data service communication, alarm communication and energy management.
It is a further object of the present invention to provide a system of the type described which includes a modular data service switching arrangement integrated into the basic security system switch to permit faster switchover and interleaving of data service and alarm and automatic meter reading data.
It is still another object of the present invention to provide a system of the type described in which data service support is independent from data rate code, format and protocol of the data service system.
It is still a further object of the present invention to provide a system of the type described which operates on the basis of a sophisticated communications protocol with error detection and retransmission to minimize false alarms and erroneous data.
It is another object of the present invention to provide a system of the type described having increased flexibility and expandability to allow for system growth in terms of both services and the number of subscribers served.